Zoe, a Burchell's zebra — the most common type of zebra— was 19. In the wild, zebras can live an average of 20 to 30 years, while in zoos, they can survive up to 40 years, according to the Woodland Park Zoo.

Not everyone agrees on whether Zoe's condition classifies as albinism, due to an ambuiguity in the how the word is defined. Some prefer the term hypomelanism, to indicate a reduction in the amount of pigment in Zoe's hair and eyes.

Credit: Three Ring Ranch

But Zoe was no ordinary zebra. With pale brown stripes and blue eyes, Zoe had a pigmentation disorder, although the researchers Live Science spoke with disagreed on what to call her condition.

The lack of consensus arises from uncertainty on how to define the term albinism, a mutation in the TYR gene that results in a change in the pigmentation of skin, eyes, hair, fur or scales.

To those who consider albinism to be only a complete lack of pigment, Zoe doesn't qualify. In this case, her condition might better be categorized as hypopigmentation, which refers to a reduction in the pigment melanin, Rebecca Bellone, an associate adjunct professor of veterinary genetics at the University of California, Davis, told Live Science.

Zoe's blue eyes and pale eyelashes are particularly striking.

Credit: Three Ring Ranch

However, to those who consider albinism to be a broader term that encompasses not only the absence of pigment but also its reduction— as William Oetting, a professor of human genetics at the University of Minnesota, does — albinism applies to Zoe.

Whatever term used, pigmentation disorders are sometimes associated with impaired vision, though Zoe may not have had vision problems. As far as Goody could tell, although Zoe wasn't the most coordinated zebra she'd seen, Zoe didn't have poor vision.

Zoe's main health problem involved the seizures she suffered from in her final years. Both Oetting and Bellone — neither of whom ever studied Zoe — thought the seizures were likely unrelated to her pigmentation disorder.

Before giving birth to Zoe at Three Ring Ranch, Zoe's mother, Oreo, who had ordinary coloring, gave birth to two other foals with Zoe's unusual pigmentation. But neither survived as long as Zoe; one was stillborn, and the other died at 5 months. Necropsies, or animal autopsies, of these foals revealed both had a liver condition, which Goody considers to be unrelated to their pigmentation disorder.

Although it appears Zoe's death was unrelated to her pigmentation disorder, some other creatures aren't so lucky. In 2003 at Zoo Barcelona, a white-furred, pink-skinned gorilla named Snowflake died of skin cancer. Living relatives of Zoe, some of whom have tan stripes like Zoe's, reside at a ranch in Kenya, though, according to Goody, they are being inbred, so their unusual pigmentation may lead — directly or indirectly — to health problems in their offspring.

Of course, there's more to pale zebras than their color.

"[Zebras] are, personality-wise, mules that have rabies," Goody joked when asked what Zoe was like. "They have an attitude about them, which is delightful in its own obnoxious way."

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Sarah Puschmann is a staff writer for Live Science. She particularly enjoys writing about ecology and evolution and has degrees in creative writing and physics. Before joining Live Science, she taught English in Korea, Costa Rica, Argentina, Sweden, and Germany. Follow her on Twitter.